Tropical Fish Care

This article covers your first steps when bringing your tropical fish home: setting up, safety precautions, and what to consider when choosing a tropical aquarium.

Picking Out a Tropical Aquarium

Choosing the right aquarium comes down to a few factors. Budget is one, since larger or better-quality aquariums cost more. The fish you want to keep is another — species that grow large or prefer to shoal in numbers, such as tiger barbs or rainbowfish, need more swimming room than a handful of small tetras. Location matters too, as you’ll need a power point nearby to run the filter, heater, and bubbler, and knowing where the tank will sit helps decide what size suits the space.

Unlike a cold water setup, every tropical aquarium needs a reliable heater to keep the water in the right range for the species you’re keeping (most sit comfortably between 24°C and 27°C). Budget for this as part of the tank, not as an optional extra.

Some tanks suit sitting on a table, but for larger glass aquariums a foam underlay is worth having, since a full tank becomes very heavy once water is added. The Foam Booth in Surry Hills can cut foam to size if you need it.

Avoid placing the aquarium in direct sun, as this leads to algae problems, and keep it away from busy walkways where it could be knocked, and away from drafts such as an open window, since draughts make it harder for the heater to hold a stable temperature.

There’s no such thing as a tank too big for a fish, though a tank can be too big for the room it’s going in. If space is limited, choose tropical species suited to a smaller footprint rather than trying to squeeze a large-growing fish into a tank it will outgrow. We stock a range of aquarium sizes in store, so it’s worth bringing your measurements in to find the best fit, or just visiting for some inspiration.

The larger the aquarium, the more stable the environment, since a bigger volume of water buffers changes in temperature and water quality more effectively. For this reason, we generally recommend getting the biggest tank your space allows.

Most of our aquariums come with a cover as standard, which helps stop fish from jumping out.

Setting Up Your Tropical Aquarium

The first rule with any tropical aquarium is to rinse everything that goes into the tank with tap water first, from nets and decorations to filters and bubblers. You never know if a product has been handled with something on someone’s hands, and fish are sensitive enough that it’s worth being careful.

Once you have everything on our checklist, it’s time to set the tank up before adding any fish.

The best approach is to set everything up around two weeks before adding fish and let the tank run on its own — this is called cycling. You can buy everything, set it up, and add fish the same day, but there’s a real risk of an ammonia spike, since the beneficial bacteria a bio starter introduces haven’t had time to establish in the filter media yet. If you do want to stock quickly, start with only a small number of fish.

To get started, rinse the inside of the tank and the gravel before adding the gravel to the bottom. Set up your filter following the instructions for your particular model, then install the heater, positioning it near the filter outlet so warmed water circulates evenly rather than pooling in one spot. Don’t switch the heater on until it’s fully submerged.

Add plants and decorations such as stones and wood, leaving a clear space at the front of the tank, since many fish like open swimming room and it makes for better viewing. Use a rinsed piece of plastic over the gravel before adding water, so the flow doesn’t dislodge it, and fill the tank slowly. Fill it properly, as many filters won’t work correctly if the water level is too low.

Add water conditioner directly to the water following the bottle’s instructions — it’s genuinely hard to overdose, and the dosing is straightforward. Add the bio starter after the conditioner has had a chance to mix in, since the chlorine in tap water that’s harmful to fish will also kill the beneficial bacteria in the bio starter.

Switch the heater on once the tank is filled and give it 24 hours to settle at a stable temperature before checking it against your thermometer.

Checklist of What You Need to Start Your Aquarium

Suitable sized tank: Think ahead to the fish’s full adult size and leave room for ornaments, hides, and plants.

Gravel: Enough to cover the base of the tank at around 3 to 5cm, which also gives plants and ornaments something to anchor into. Rinse it in a bucket under the tap until the water runs clear before adding it.

Filtration: We stock a range of filters in store, and some tanks come with one included. Make sure yours is rated for your tank size or larger — filters usually list a recommended litre rating, so check this against your tank’s volume. The filter handles the nitrification process: fish waste produces ammonia, beneficial bacteria convert this to nitrite, and further bacteria convert that nitrite into the far less harmful nitrate, which is then removed through regular water changes.

Heater and thermometer: Non-negotiable for tropical fish. Choose a heater rated for your tank’s volume and check the temperature daily with a separate thermometer, since a heater can fail without any obvious sign until the water has already drifted out of range.

Lighting: Brings out the colours in your fish, supports plant growth if you’re keeping live plants, and adds to the overall look of the tank.

Aeration and bubbler: An air pump that oxygenates the water by pushing air through an airline. Fish can struggle without enough dissolved oxygen, so this keeps the water healthier and better circulated.

Gravel vacuum: Cuts down cleaning time while improving water quality, since it suctions waste and debris straight out of the gravel and into a bucket, doubling as a water change.

Fish net: For moving fish or handling anything else during tank maintenance.

Food: Ask our team which option suits your fish, whether that’s flakes, pellets, or frozen feed.

Water conditioner: Needed whenever you add tap water to the tank, since it neutralises chlorine and metals that would otherwise burn a fish’s gills.

Bio starter: Introduces the beneficial bacteria your filter needs to run the nitrogen cycle properly.

Waste controller: Converts waste such as leftover food and faeces into beneficial bacteria, cutting down on cleaning and keeping the tank healthier for longer.

Salt: A staple for goldfish and other cold water species, but not something to add by default to a tropical tank. Many tropical fish, particularly scaleless species like corydoras and loaches, and salt-sensitive tetras, don’t tolerate it well. If you’re ever unsure whether a species can handle it, ask our team before adding any.

Algae cleaner: Every aquarium develops some algae. Choose a cleaner made from a material that won’t scratch the glass, such as a magnetic floating cleaner or a soft scrub pad. Suckerfish and certain snail species will also help keep soft algae growth down and make interesting additions in their own right.

pH test kit: Water quality depends heavily on pH, and Sydney tap water can fluctuate. A simple test kit takes the guesswork out of monitoring it.

Before your fish arrive: Have a holding container, or the aquarium itself, filled with conditioned, heated tap water ready before your fish arrive. All Sydney tap water needs treating to remove chloramine before it’s safe for anything with gills. Use aquarium salt only, never table salt, if salt is appropriate for the species you’re keeping.

The Arrival of New Fish

Once you’ve chosen your fish and brought them home, make sure your tropical aquarium is fully set up from the checklist above, with the heater holding a stable temperature and the water conditioned. Check the pH before your fish go in.

Let the sealed fish bag float in the aquarium water for 10 to 15 minutes so the fish can acclimate to the tank’s temperature, since there’s usually a difference between the bag water and the tank. Releasing fish straight into a different temperature can shock them and lead to problems well after the fact. For sensitive tropical species, a slower drip acclimation over 20 to 30 minutes is worth the extra time. After acclimating, use a net to gently move the fish into the tank rather than tipping the bag water in, and discard the bag water down the sink.

Don’t feed your fish in the first 24 hours. They’re often stressed from the move, and feeding too soon does more harm than good.

Maintaining Your Tropical Aquarium

Regular maintenance is what keeps a tropical aquarium running well. In the wild, natural processes handle waste breakdown; in a glass tank, that job falls to you, or the filter clogs, the water quality drops, and fish suffer for it.

Maintenance is a balancing act. Over-cleaning is just as much of a problem as under-cleaning, since scrubbing the filter too thoroughly wipes out the beneficial bacteria colony and can trigger an ammonia spike.

Every 24 hours: Check on your fish at feeding time, looking over their condition and counting them. If it takes longer than 30 seconds for them to finish their food, you’re feeding too much. Check the filter flow, the bubbler, and the lights are all working, and glance at the thermometer to confirm the heater is holding steady.

Every 2 weeks: Clean the glass, gently wipe down ornaments and any fake plants, and use a gravel vacuum to do a water change, which clears waste from the substrate and helps bring nitrate levels down. A 30% change is generally enough, and conditioner should go in just before the fresh tap water. The whole process takes about 10 minutes. Use the water you’ve siphoned out to rinse filter media and cartridges, which keeps the bacteria colony alive during the clean. Replace old filter media gradually rather than all at once, so the colony has time to re-establish, and swap in the rest around four weeks later.

Once a month: Before your next water change, test the pH, ammonia, nitrite, and nitrate levels.

Live plants: Remove any dead leaves and trim back growth that’s crowding the tank.

Aquarium Decorations Sydney

Whatever decorations you choose, whether natural or manufactured, rinse them before adding them to the tank. We stock a range of driftwood, including pieces that come pre-soaked and ready to go, some with a slow-growing plant called anubias already attached — a popular option that adds real visual interest to a tropical setup. We also carry dry wood, which needs soaking for around two weeks until it sinks and stops releasing tannins into the water.

What should I do with the water in the shipping bag?

Flush it down the sink rather than adding it to your tank. It carries waste products the fish gave off during transport, and pouring it into your aquarium introduces exactly what you’re trying to keep out of a newly cycled tank.

Why is the shipping water blue?

That colour comes from a medication we add before transport to reduce stress on the fish during the trip. It’s a normal part of how we ship live fish and nothing to be concerned about once the fish are settled into their new tank.

Should I feed my fish as soon as they arrive?

Hold off for a full day first. Newly arrived fish need time to recover from the move and adjust to their new surroundings before their gut is ready to process food, so feeding too early tends to do more harm than good.

How much should I feed my fish?

Only give them what they can finish within a few minutes, once a day. Leftover food breaks down and feeds bacteria in the tank, which can use up dissolved oxygen and put stress on your fish and anything else living in the aquarium.

How do I know if my heater is working properly?

Check your thermometer daily rather than trusting the heater’s dial alone, since a stuck thermostat can leave water too hot or too cold with no obvious warning sign. A consistent reading in your target range over several days is the clearest indication that it’s doing its job.

How can I tell if my fish are healthy?

A healthy fish stays active with its fins held up and spread out. Watch for drooping or clamped fins, fuzzy patches, trailing slime, or a fish that hides constantly, and separate anything showing these signs before it can affect the rest of the tank.